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authorAndrii Nakryiko <andriin@fb.com>2019-12-18 16:28:34 -0800
committerAlexei Starovoitov <ast@kernel.org>2019-12-18 17:33:36 -0800
commit81bfdd087bf31a87c5ff25cc7004d5308954a35c (patch)
tree364a9d81d8f7bd736c22c12e5e7795be1fd50dd6 /tools/lib
parentd69587062c347314a019cf6ee27f2e4b494868e1 (diff)
downloadlinux-81bfdd087bf31a87c5ff25cc7004d5308954a35c.tar.bz2
libbpf: Put Kconfig externs into .kconfig section
Move Kconfig-provided externs into custom .kconfig section. Add __kconfig into bpf_helpers.h for user convenience. Update selftests accordingly. Suggested-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20191219002837.3074619-2-andriin@fb.com
Diffstat (limited to 'tools/lib')
-rw-r--r--tools/lib/bpf/bpf_helpers.h2
-rw-r--r--tools/lib/bpf/libbpf.c58
2 files changed, 37 insertions, 23 deletions
diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
index aa46700075e1..f69cc208778a 100644
--- a/tools/lib/bpf/bpf_helpers.h
+++ b/tools/lib/bpf/bpf_helpers.h
@@ -53,4 +53,6 @@ enum libbpf_tristate {
TRI_MODULE = 2,
};
+#define __kconfig __attribute__((section(".kconfig")))
+
#endif
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 2a341a5b9f63..0772eb3254e2 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -231,21 +231,21 @@ struct bpf_program {
#define DATA_SEC ".data"
#define BSS_SEC ".bss"
#define RODATA_SEC ".rodata"
-#define EXTERN_SEC ".extern"
+#define KCONFIG_SEC ".kconfig"
enum libbpf_map_type {
LIBBPF_MAP_UNSPEC,
LIBBPF_MAP_DATA,
LIBBPF_MAP_BSS,
LIBBPF_MAP_RODATA,
- LIBBPF_MAP_EXTERN,
+ LIBBPF_MAP_KCONFIG,
};
static const char * const libbpf_type_to_btf_name[] = {
[LIBBPF_MAP_DATA] = DATA_SEC,
[LIBBPF_MAP_BSS] = BSS_SEC,
[LIBBPF_MAP_RODATA] = RODATA_SEC,
- [LIBBPF_MAP_EXTERN] = EXTERN_SEC,
+ [LIBBPF_MAP_KCONFIG] = KCONFIG_SEC,
};
struct bpf_map {
@@ -305,7 +305,7 @@ struct bpf_object {
char *kconfig_path;
struct extern_desc *externs;
int nr_extern;
- int extern_map_idx;
+ int kconfig_map_idx;
bool loaded;
bool has_pseudo_calls;
@@ -606,7 +606,7 @@ static struct bpf_object *bpf_object__new(const char *path,
obj->efile.data_shndx = -1;
obj->efile.rodata_shndx = -1;
obj->efile.bss_shndx = -1;
- obj->extern_map_idx = -1;
+ obj->kconfig_map_idx = -1;
obj->kern_version = get_kernel_version();
obj->loaded = false;
@@ -902,11 +902,25 @@ static size_t bpf_map_mmap_sz(const struct bpf_map *map)
return map_sz;
}
+static char *internal_map_name(struct bpf_object *obj,
+ enum libbpf_map_type type)
+{
+ char map_name[BPF_OBJ_NAME_LEN];
+ const char *sfx = libbpf_type_to_btf_name[type];
+ int sfx_len = max((size_t)7, strlen(sfx));
+ int pfx_len = min((size_t)BPF_OBJ_NAME_LEN - sfx_len - 1,
+ strlen(obj->name));
+
+ snprintf(map_name, sizeof(map_name), "%.*s%.*s", pfx_len, obj->name,
+ sfx_len, libbpf_type_to_btf_name[type]);
+
+ return strdup(map_name);
+}
+
static int
bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
int sec_idx, void *data, size_t data_sz)
{
- char map_name[BPF_OBJ_NAME_LEN];
struct bpf_map_def *def;
struct bpf_map *map;
int err;
@@ -918,9 +932,7 @@ bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
map->libbpf_type = type;
map->sec_idx = sec_idx;
map->sec_offset = 0;
- snprintf(map_name, sizeof(map_name), "%.8s%.7s", obj->name,
- libbpf_type_to_btf_name[type]);
- map->name = strdup(map_name);
+ map->name = internal_map_name(obj, type);
if (!map->name) {
pr_warn("failed to alloc map name\n");
return -ENOMEM;
@@ -931,12 +943,12 @@ bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
def->key_size = sizeof(int);
def->value_size = data_sz;
def->max_entries = 1;
- def->map_flags = type == LIBBPF_MAP_RODATA || type == LIBBPF_MAP_EXTERN
+ def->map_flags = type == LIBBPF_MAP_RODATA || type == LIBBPF_MAP_KCONFIG
? BPF_F_RDONLY_PROG : 0;
def->map_flags |= BPF_F_MMAPABLE;
pr_debug("map '%s' (global data): at sec_idx %d, offset %zu, flags %x.\n",
- map_name, map->sec_idx, map->sec_offset, def->map_flags);
+ map->name, map->sec_idx, map->sec_offset, def->map_flags);
map->mmaped = mmap(NULL, bpf_map_mmap_sz(map), PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_ANONYMOUS, -1, 0);
@@ -1232,7 +1244,7 @@ out:
return err;
}
-static int bpf_object__init_extern_map(struct bpf_object *obj)
+static int bpf_object__init_kconfig_map(struct bpf_object *obj)
{
struct extern_desc *last_ext;
size_t map_sz;
@@ -1244,13 +1256,13 @@ static int bpf_object__init_extern_map(struct bpf_object *obj)
last_ext = &obj->externs[obj->nr_extern - 1];
map_sz = last_ext->data_off + last_ext->sz;
- err = bpf_object__init_internal_map(obj, LIBBPF_MAP_EXTERN,
+ err = bpf_object__init_internal_map(obj, LIBBPF_MAP_KCONFIG,
obj->efile.symbols_shndx,
NULL, map_sz);
if (err)
return err;
- obj->extern_map_idx = obj->nr_maps - 1;
+ obj->kconfig_map_idx = obj->nr_maps - 1;
return 0;
}
@@ -1742,7 +1754,7 @@ static int bpf_object__init_maps(struct bpf_object *obj,
err = bpf_object__init_user_maps(obj, strict);
err = err ?: bpf_object__init_user_btf_maps(obj, strict, pin_root_path);
err = err ?: bpf_object__init_global_data_maps(obj);
- err = err ?: bpf_object__init_extern_map(obj);
+ err = err ?: bpf_object__init_kconfig_map(obj);
if (err)
return err;
@@ -2269,9 +2281,9 @@ static int bpf_object__collect_externs(struct bpf_object *obj)
i, ext->sym_idx, ext->data_off, ext->name);
}
- btf_id = btf__find_by_name(obj->btf, EXTERN_SEC);
+ btf_id = btf__find_by_name(obj->btf, KCONFIG_SEC);
if (btf_id <= 0) {
- pr_warn("no BTF info found for '%s' datasec\n", EXTERN_SEC);
+ pr_warn("no BTF info found for '%s' datasec\n", KCONFIG_SEC);
return -ESRCH;
}
@@ -2361,7 +2373,7 @@ bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx)
else if (shndx == obj->efile.rodata_shndx)
return LIBBPF_MAP_RODATA;
else if (shndx == obj->efile.symbols_shndx)
- return LIBBPF_MAP_EXTERN;
+ return LIBBPF_MAP_KCONFIG;
else
return LIBBPF_MAP_UNSPEC;
}
@@ -2908,8 +2920,8 @@ bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map)
return err;
}
- /* Freeze .rodata and .extern map as read-only from syscall side. */
- if (map_type == LIBBPF_MAP_RODATA || map_type == LIBBPF_MAP_EXTERN) {
+ /* Freeze .rodata and .kconfig map as read-only from syscall side. */
+ if (map_type == LIBBPF_MAP_RODATA || map_type == LIBBPF_MAP_KCONFIG) {
err = bpf_map_freeze(map->fd);
if (err) {
err = -errno;
@@ -4264,7 +4276,7 @@ bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
break;
case RELO_EXTERN:
insn[0].src_reg = BPF_PSEUDO_MAP_VALUE;
- insn[0].imm = obj->maps[obj->extern_map_idx].fd;
+ insn[0].imm = obj->maps[obj->kconfig_map_idx].fd;
insn[1].imm = relo->sym_off;
break;
case RELO_CALL:
@@ -4743,7 +4755,7 @@ static int bpf_object__resolve_externs(struct bpf_object *obj,
if (obj->nr_extern == 0)
return 0;
- data = obj->maps[obj->extern_map_idx].mmaped;
+ data = obj->maps[obj->kconfig_map_idx].mmaped;
for (i = 0; i < obj->nr_extern; i++) {
ext = &obj->externs[i];
@@ -7546,7 +7558,7 @@ int bpf_object__open_skeleton(struct bpf_object_skeleton *s,
}
/* externs shouldn't be pre-setup from user code */
- if (mmaped && (*map)->libbpf_type != LIBBPF_MAP_EXTERN)
+ if (mmaped && (*map)->libbpf_type != LIBBPF_MAP_KCONFIG)
*mmaped = (*map)->mmaped;
}